公开(公告)号：US20240376577A1

公开(公告)日：2024-11-14

申请号：US18682114

申请日：2022-06-21

Applicant: JFE STEEL CORPORATION

Inventor： Yuji TANAKA ,  Kazuki ENDOH ,  Hidekazu MINAMI ,  Junya TOBATA ,  Yuki TOJI

IPC: C22C38/04 ,  C21D6/00 ,  C21D8/02 ,  C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C23C2/06

Abstract: The steel sheet comprising a chemical composition containing C, Si, Mn, P, S, Al, N, Ti, Nb, and B, with the balance being Fe and inevitable impurities, and satisfying predetermined formula (1), in which the total area ratio of martensite and bainite is 95% or more, the grain size of prior austenite grains is 10 μm or less, the B concentration at a prior austenite grain boundary is 0.10% or more in mass %, the C concentration at the prior austenite grain boundary is 1.5 times or more than the C content in the steel, the amount of precipitated Fe is 200 mass ppm or less, and for a defined in predetermined formula (2), a ratio of adislocation on dislocation to agrain boundary on the prior austenite grain boundary: adislocation/agrain boundary is 1.3 or more.

公开(公告)号：US20230374622A1

公开(公告)日：2023-11-23

申请号：US18247071

申请日：2021-08-05

Applicant: JFE STEEL CORPORATION

Inventor： Yuji TANAKA ,  Masaki TADA ,  Yuki TOJI ,  Shinsuke KOMINE ,  Yoshie OBATA ,  Yusuke KIMATA

IPC: C21D9/46 ,  C22C38/60 ,  C22C38/38 ,  C22C38/34 ,  C22C38/32 ,  C22C38/28 ,  C22C38/26 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/10 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C21D1/18 ,  C21D6/00

CPC classification number: C21D9/46 ,  C22C38/60 ,  C22C38/38 ,  C22C38/34 ,  C22C38/32 ,  C22C38/28 ,  C22C38/26 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/10 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/002 ,  C22C38/001 ,  C22C38/005 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C21D1/18 ,  C21D6/001 ,  C21D6/002 ,  C21D6/005 ,  C21D6/007 ,  C21D6/008 ,  C21D2211/005 ,  C21D2211/008 ,  C21D2211/002 ,  C21D2211/001

Abstract: A high-strength cold-rolled steel sheet comprises: a chemical composition that contains C, Si, Mn, P, S, N, Al, Ti, Nb, and B with a balance consisting of Fe and inevitable impurities, and satisfies [mol % N]/[mol % Ti]